Overlapping IP address solution in AWS

Question

Dear Team - As per https://aws.amazon.com/blogs/networking-and-content-delivery/connecting-networks-with-overlapping-ip-ranges/,

```
 Some applications may not work with this solution as applications must present as a single TCP port. If you have an application that uses UDP or has multiple TCP ports and the clients must maintain back-end server affinity then PrivateLink isn’t appropriate for you.
```

However, i wanted to know if AWS has any other solution to connect over UDP port with overlapping IP address ?

Thanks

Accepted Answer

That is correct PrivateLink supports TCP protocol only (as of today), there is also VPC Lattice which allows connectivity between VPCs using overlapping CIDR but it supports HTTP/HTTPS and gRPC protocols only (as of today)

Take a look at solution described in this Whitepaper which explains use of Private NAT gateway for connectivity between 2 VPCs using overlapping IP CIDRs or for connectivity towards on-premises network.

https://docs.aws.amazon.com/whitepapers/latest/building-scalable-secure-multi-vpc-network-infrastructure/private-nat-gateway.html

Note that the AWS NAT gateway supports SNAT (Source NAT) only, for more advanced NATing scenarios (DNAT etc) you can look at 3rd party firewall virtual appliances or NAT instances.

In general it is best to just avoid using overlapping IP space.

Overlapping IP address solution in AWS

Relevant content